Fluids and Electrolytes - Dr. Herring Review

Question 1

In the brain, what is going to determine if fluid stays in the vasculature/pulls into the vasculature or pushes into the interstitium?

Answer 1

Blood-Brain Barrier
Sodium is less permeable. Making it the primary determinant over plasma proteins.

Question 2

You give an isotonic solution into the intravascular space. What is going to happen to that solution?

Answer 2

A portion will stay in the intravascular space, but a portion of it, ~75%, will be lost to the interstitial space to reach equilibrium.

Question 3

HESes are associated with?
Could you pick out what they are not associated with?

Answer 3

Kidney injury
Dialysis requirements
coagulopathy
sepsis
and increased mortality

Question 4

What would be some reliable means for determining where your patient is on the Frank-Starling Curve?

Question 5

What might happen if you did a volume resuscitation with Normal Saline?

Answer 5

Hyperchloremia - Metabolic Acidosis

Question 6

If you hypoventilated a patient - what would that do to your acid-base balance? Therefore, what would it do to your electrolytes?

Answer 6

Create respiratory acidosis –> more calcium and potassium shifts or is released into intravascular fluid.

Question 7

You need to do an emergent C-Section on an eclamptic patient; what anesthetic drug has an increased risk profile in that circumstance?
(typically because of an electrolyte abnormality)

Answer 7

Magnesium potentiates the effects of Nondepolarizing neuromuscular agents. May need extra reversal agent.
Stop mag and reverse with CaCl

Question 8

Pts who can receive colloids:

Answer 8

-Volume loss not from active bleeding
-Hypovolemic pts with Intact glycocalyx
- Pts with lower capillary oncotic pressure such as liver pts with
hypoalbuminemia

Question 9

Pts who should not receive colloids/albumin:

Answer 9

Neurotrauma
Endothelial injuries / impaired glycocalyx —> pulm edema, end-organ damage (Sepsis, Lg Vascular Traumas)
Hypocalcemia
Hyperglycemia (DM)

Question 10

If you need to expand the plasma volume in a patient with a traumatic head injury, what fluid would you pick?

Answer 10

Hypertonic Saline Solutions of 3% or greater.
Promote volume expansion that mobilize intracellular and interstitial fluid into the vascular space. May protect patients with intracranial hypertension.

Question 11

Fluid in the capillary bed going from the capillary side to interstitial or interstitial to the capillary. What changes would you expect if the patient had a low cardiac output state?

Answer 11

TBD waiting for Dr. Herring clarification.
Acute drop CO: fluid will enter intravascular space

Chronic drop: fluid accumulates and then reenters interstitial space cause edema

Question 12

Calculate a maintenance fluid rate using the 4:2:1 rule.

Answer 12

4ml/kg for the first 10kgs
2ml/kg for the second 10kg
1ml/kg for the remaining

If greater than 20kg, add 40 to find the maintenance rate

Question 13

If you needed to devise a fluid plan for a hypovolemic patient, what fluid would you choose?

Answer 13

Isotonic: LR or NS

Question 14

Your patient is going to have surgery; they’re going to have an incision; what things can lead to evaporative losses?

Answer 14

Sweat, Breathing, Surgical exposure of body cavaties

Question 15

Your patient has Hyperkalemia and you have these EKG changes: Loss of P wave and widening QRS; immediate effective therapy is indicated, what do you administer?

Answer 15

1. IV Calcium Chloride - 10mL of 10% CaCl over 10-min period
   or
   10mL of 10% Calcium Gluconate over 3-5min
2. IV Sodium Bicarb, 50-100mEq over 10-20min

Question 16

Which yields more ionized calcium, CaCl or CaGluconate?

Answer 16

CaCl = 27mg/mL
Gluconate = 9mg/mL

Question 17

What is the onset of Calcium Chloride or Calcium Gluconate?

Answer 17

1-3 minutes

Question 18

What is the duration of action of Calcium Chloride or Calcium Gluconate?

Answer 18

30-60minutes

Question 19

Why give calcium for hyperkalemia?

Answer 19

Stabilizes cardiac membrane

Question 20

Bicarbonate administration for Loss of P wave and widening QRS due to hyperkalemia takes how long to take effect?

Answer 20

5-10minutes

Question 21

Bicarbonate administration for loss of P wave and widening QRS due to hyperkalemia lasts for how long?

Answer 21

1-2 hours

Question 22

Bicarbonate administration for Loss of P wave and widening QRS due to hyperkalemia has what mechanism of action?

Answer 22

Shifts potassium intracellularly

Question 23

Your patient has hyperkalemia and Peaked T waves that need prompt therapy; what do you do?

Answer 23

1. Glucose and Insulin Infusion:
   IV of 50mL D50W and five units regular insulin
2. Urgent hemodialysis

Question 24

Administration of IV D50W 50mL and five units regular insulin for hyperkalemia takes how long to onset?

Answer 24

30 minutes

Question 25

Administration of IV D50W 50mL and five units of regular insulin for hyperkalemia has a therapeutic duration of?

Answer 25

4-6 hours

Question 26

What is the mechanism of action of glucose and insulin administration in a hyperkalemic patient?

Answer 26

Shifts potassium intracellularly.

Question 27

What should you do if the patient has hyperkalemia but no EKG changes?

Answer 27

1. Administer potassium-binding resins in GI tract
2. Promotion of renal excretion via loop diuretics.

Question 28

How long does oral potassium binding resins take to onset? Have a duration of?

Answer 28

Onset: 1-2 hours
Duration: 4-6 hours

Question 29

Administration of furosemide 40mg for hyperkalemia usually has an onset of? And a duration of?

Answer 29

Onset: 15-30 minutes
Duration: 2-3 hours